I'm sorry i don't have a good answer for you. I should be getting my Angel at the end of the week. I will however let you know that a size 357 or 303 button cell battery (i got energizer) is the same as an LR44, wich is what the Angel's take. And you can find them in 3 packs at walmart (depending on where you are from of course) for just under $5.
Well yes you could get them on Ebay, if someone was selling them. ut they arn't out in Europe (If thats where you're from) they're out in America and Japan from what I've heard.